Other Assets by Major Categories (Detail) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Net deferred tax assets (net of valuation allowance)	$ 362,036	$ 388,466	$ 340,146
Investments under the equity method	299,316	299,185	98,234
Bank-owned life insurance program	240,314	237,997	235,499
Prepaid FDIC insurance assessment	101,919	147,513	179,130
Other prepaid expenses	99,833	75,149	161,963
Derivative assets	68,376	72,510	79,571
Trade receivables from brokers and counterparties	37,196	347	73,110
Others	184,853	228,720	221,651
Total other assets	$ 1,393,843	$ 1,449,887	$ 1,389,304